Plenty of Tweeps is a dating site for Twitter users. The idea is that a person's Twitter activity stream provides a unique window into their life, something a little more authentic than a typical online dating profile.
You don't need to be a hardcore Twitter user to make use of the site though. Going through the signup process will help you create a Twitter account if you don't already have one, and allow you to easily find cool Twitter peeps in your area.
You can also upload photos and fill out a profile, which is particularly useful if you haven't tweeted much. :)